Organic amendments

Manure applications improve quality and yields of vine crops. Composted manures help to improve soil texture and drainage, and act as slow-release fertilizers. Apply up to 20,000 lbs/Acre (10 MT/Acre) as a complement to calibrated chemical fertilizer applications. Often, chicken manure is added at amounts of up to 1 lb/hill and it is worked into the soil.

Fertigation     

Available soluble fertilizers may be injected through the irrigation system in place of sulfate of ammonia and muriate of potash. N levels of 200 ppm and K levels at 250 ppm in fertigation solution are recommended for maximum cucumber yields. A schedule for fertilizer rate applications in cucumber is listed in Table 3. Before using chemicals through irrigation systems, be aware of any regulations which may apply.

Table 3. Timing and Fertilizer Injection Rates Recommended for Cucumbers, beginning at Transplanting.

       Timing Fertilizer Rates

       (Weeks after transplanting) (lbs/Acre/week)

       1st to 3rd week 2.5 lbs of 20-10-20

       4th to 8th week 5 lbs of 20-20-20

       9th to 16th week 6.25 lbs of 20-20-20

       Epson salt 5 lbs at 4th, 8th, 12th week

Nutrient Tissue Analysis

      Periodic nutrient analysis of foliage tissue is useful to obtain an estimate of a crop's nutritional status and serve as a record of crop performance. The tissue analysis should be calibrated with soil fertility levels, according to soil samples taken before planting. For tissue analysis, collect a young mature whole leaf (petiole and leaves) located below the last open flower cluster. A representative tissue sample from a field plot will consist of 25 to 50 collected leaves free of insects or disease. Collect samples prior to the fruiting stage. Recommended optimum ranges for cucumbers are found in Table 4

             Table 4. Recommended Tissue Nutrient Ranges for Cucumber

   

      Nutrient Target Level (1)

      N 3.3-4.0%

      P 0.4-0.8%

      K 2.8-4.0%

      Ca 1.8-2.5%

      Mg 0.4-0.5%

      S 0.3%

     Fe 108 ppm

     Zn 23 ppm

     Mn 60 ppm

     Cu 8 ppm

     B 25 ppm

(1)  Percent dry matter content. Nutrient level of young mature leaf at the pre-fruiting stage (5th-6th leaf from apex). 

CULTURE AND MANAGEMENT PRACTICES

  In typical commercial operations, cucumbers are grown in polyethylene-mulched beds with drip irrigation. Water and nutrients inputs are closely monitored and adjusted with drip irrigation. The plastic mulch helps control weeds, improves efficient use of water and fertilizer, and reduces incidence of fruit rots. Yields of ground culture are 40-80% of those obtained with mulch culture. Cucumbers are susceptible to damage from wind and need the protection provided by windbreaks in wind-prone areas. Examples of commonly used windbreaks include 'Tropical Coral' Tall Erythrina (Erythrina variegata L.), and wild cane (Saccharum spontaneum moentai). Other suitable windbreaks may also be used. Where annual windbreaks are used, an in-field rotation may be conducted for the following crop by rototilling the row where the windbreak was grown, planting in the row, and preparing the bed in that area.

      Time to Plant

    In Hawaii, cucumbers are planted year round from sea level to 3,000 feet (0-1000 m) elevation, and from April to October at elevations above 3,000 ft (1000 m). Often cucumbers at high elevations become bitter in the winter season.

Field Preparation

The field may require plowing or subsoiling to break a hard pan. The field is then disked and/or tilled to break up soil clods. Soils with poor drainage benefit from manure or other organic matter materials incorporated into the soil. If a soil amendment such as lime is needed, broadcast it before plowing and incorporate at a depth of 10-12 inches 8-12 weeks prior to planting. This allows the lime to react with the soil to correct pH assuming sufficient moisture is available in the soil. If a nematicide is used, apply at least two weeks prior to planting in light soils and three weeks prior to planting in heavy soils. Cover crops should be turned over 2-4 weeks (earlier for the ones that decompose faster) prior to planting cucumbers to allow for litter decomposition.

Propagation

    Cucumbers are both direct seeded and transplanted in Hawaii. Proper soil temperatures for seed germination range between 55-95F (13-35C). Thinning is conducted in two operations for direct seeded crops . The first thinning occurs at the two leaf stage leaving 4-5 plants per hill. The final thinning takes place about a month after seeding, leaving two plants per hill. Cucumbers can be transplanted when adverse growing conditions are expected during the initial growing stages, when expensive seed is used, or for special operations as in hydroponic cultures. About 1-2 lbs/Acre of seed is required for direct-seeded cucumbers (there are about 1100 seed per ounze). Cucumber inoculation with Vesicular-Arbuscular Mycorrhiza fungi Glomus spp., which has been shown to improve nutrient uptake in other crops, also improved tolerance to salt stress and prevented attack from damping-off, Pythium ultimum, in cucumbers. However, Glomulus seed inoculants are not currently commercially available. Seed at a depth of 3/4-1 inch.

Spacing

    Many variations of plant spacing are used. The rows are spaced 4-6 feet to allow space for spraying and harvesting in trellised fields. Plant spacing within the row is 1-5 feet, depending on the number of plants per hill, and on vine vigor of the particular cultivar. Cultivars with vigorous lateral growth such as Burpee Hybrid II should have an increased spacing. Cucumbers grown in plastic mulch may be planted two rows to a bed with rows in the bed spaced 9 inches. Greenhouse and hydroponic grown cucumbers are generally planted closer, and may require pruning.

Training

   Cucumbers may be grown in trellises or in ground culture. Trellis the oriental slicing types to prevent the development of crooked fruits. Yields of Fancy and No. 1 fruits for non-trellised cucumbers will be 40-75% of those obtained with staked cucumbers. The major advantages and disadvantages of trellising a cucumber crop are listed in Table 5.

Table 5. Advantages and Disadvantages of Trellised-Cucumbers

   

Advantages

   a. Increased harvesting efficiency and greater yields

   b. Improved pest management

   c. Straighter fruits

   d. Uniform fruit color

   e. Reduction of fruit loss to soil diseases

   f. More plants per acre due to closer rows.